/*
 * Copyright 2012-2021 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.boot.context.properties;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

/**
 * 注解，用于指示配置属性应通过构造函数参数绑定，
 * 而不是通过调用 setter 方法绑定。可以添加在类型级别（如果存在唯一构造函数）
 * 或实际要使用的构造函数上。
 * <p>
 * 注意：使用构造函数绑定时，类必须通过
 * {@link EnableConfigurationProperties @EnableConfigurationProperties} 或配置属性扫描启用。
 * 构造函数绑定不能用于通过常规 Spring 机制创建的 Bean
 * （例如 {@link org.springframework.stereotype.Component @Component} Bean、
 * 通过 {@link org.springframework.context.annotation.Bean @Bean} 方法创建的 Bean，
 * 或通过 {@link org.springframework.context.annotation.Import @Import} 加载的 Bean）。
 *
 * @author Phillip Webb
 * @since 2.2.0
 * @see ConfigurationProperties
 */
@Target({ ElementType.TYPE, ElementType.CONSTRUCTOR })
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface ConstructorBinding {

}
